docs: def rbf(ra, coeff, mag):
      """
      Calculate the median ground motion for a given magnitude and distance
  
      :param ra:
          Distance value [km]
      :param coeff:
          The set of coefficients
      :param mag:
          Magnitude value
      :returns:
  
      """
      a1ca, a1cb, a1cc, a1cd, a1ce, a2ca, a2cb, a2cc, a2cd, a2ce = gc(coeff, mag)
      term1 = a1ca + a1cb * mag + a1cc * np.log(ra + a1cd*np.exp(a1ce*mag))
      term2 = a2ca + a2cb * mag
      term3 = a2cd*np.exp(a2ce*mag)
      return np.exp((term1 - term2) / a2cc) - term3